Separable electrical connecter



June 13, 1939. ooms SEPARABLE ELECTRICAL CONNECTER Filed April 5, 1955 INVENT OR.

y Q61; ii A TTORNEY.

Patented June 13, 1939 UNITED STATES PATENT OFFICE 5 Claims.

This invention relates to separable electric connecter plugs, of the type commonly employed in connecting lamps and other electrical appliances to a source of electrical current supply.

Attachment plug caps of the type commonly used today are a cause of considerable annoyance because of the frequency with which the strands of the electric 'cord to which they are attached, become broken within the body of the plug and elsewhere, due'in most cases to frequent and recurrent twisting of the cord in effecting its attachment to a complementary plug part, as for example, a flush-type receptacle. The twisting of the cord is caused primarily by the difficulty,

in effecting the plug connection which requires that the contacts of the complementary plug parts be brought into substantial alignment or registry before connection is possible, and in.

doing this, most people will rotate the plug cap a certain amount and usually always in the same direction, thus causing twisting of the cord and breaking of the strands of the cord at the place of their attachment to the contact members. of the plug cap.

It is the object of this invention to provide a plug of the class described in which the two cooperating parts of the plug may be quickly and readily connected. by an unskilled person even in the dark; which shall make good electrical contact; which shall have terminal conductors adapted for detachable interlocking engagement; which shall be safe in use; and which shall obviate twisting of the electrical wires connected to the plug parts in connecting the plug cap to a complementary connecter.

With these and other objects in view, the invention consists in the novel construction, arrangement and combination of parts, hereinafter illustrated and described in some of its embodiments in the accompanying drawing, and particularly pointed out in the appended claims.

In the accompanying drawing, Figure 1 is a plan view of a flush-type receptacle, illustrative of one form of the invention; Figure 2 is a central sectional view of the receptacle shown in Figure 1; Figure 3 is a plan view of an attachment plug cap having blades adapted for connection with the contact terminals of the cooperating receptacle shown in Figure 1; Figure 4 is a side elevational view of the plug cap shown in Figure 3; Figure 5 is a plan view of a modification of the invention, illustrating a screw shell or plug body adapted to receive an attachment plug cap; Figure 6 is a side elevational view, partly in section, of the plug body shown in Figure 5; Figure '7 is a plan view of an attachment plug cap having contact blades adapted for connection with the contact terminals of the plug body shown in Figure 5; Figure 8 is a side elevational view of the attachment plug cap 5 shown in Figure 7; Figure 9 is a plan view of an adapter illustrating another modification of the invention; Figure 10 is a side elcvational View, partly in section, of the adapter. shown in Figure 9; Figure 11 is a plan view of an attachment plug cap adapted for connection with certain of the contact terminal members of the adapter shown in Figure 9; Figure 12 is a side elevationai view of the plug cap shown in Figure 11; Figure 13 is a plan view of a surface-type receptacle illustrating a modified form of connecter adapted for receiving plug caps of the type shown in Figures 4 and 8; and Figure 14 is a side elevational view, partly in section, of the receptacle shown in Figure 13. 20

In the form of the invention illustrated in Figures 1 to 4, the cooperating parts of the separable connecter comprise a flush-type receptacle l and an attachment plug cap 2, the same having terminal blades adapted for detachable interlocking engagement with the" contact members of said receptacle. The receptacle l comprises a body 3 formed from an electrically non-conducting material, such as, porcelain, phenolic or coldmolded composition, or, other insulating material suitable for the purpose.

In the face of this body, there is provided an annular groove 4 which is divided into two halves by means of spacersS, 5 which may be integrally formed with the body part 3 of the receptacle. Inner and outer circularly curved contact members 6 and I are received in annular grooves 8, 8 formed in the body of the plug beneath the groove 4. The contact members I, l are offset at Ill to provide an annular notch for interlock- 0 ing engagement with the contact blades of the plug cap 2. The contact members 5 and I may be formed from phosphor-bronze or some metal equivalent in physical properties. The said contact members are connected in any suitable manner, such as, by soldered joints to the currentcarrying strands or conductors 9, 9.

A base plate H and a supporting bar l2 are secured to the body of the plug by any suitable means, such as, the screw I3. The ends of the bar l2 are provided with holes l4, M for reception of the securement screws (not shown) of the receptacle by means of which the same is mounted in a standard flush-type device or on a metal plate (not shown). The cooperating attachment plug cap comprises a body part l5 having contact blades l5, it connected to the conductor strands I1, I! of a flexible cord or cable l8.

The plug cap shown in Figures 3 and 4 differs from the conventional plug cap only in that the contact blades are notched as at 20 for interlocking engagement with the oifset portions Id of the contacts I of the receptacle. The contacts 5 and l of the receptacle l are resilient so that the receptacle is also adapted without change for reception of the blades of a standard attachment plug cap. When intended to be used in this manner, the offsettings Ill, It may be omitted, if desired, in forming the contacts 1, 1 of the receptacle.-

The face of the body 3 of the receptacle is slightly recessed so as to provide a shoulder 2| closely adjacent to the annular slot 4, thus providing a means for locating the terminal blades of the plug cap when it is desired to effect connection with the receptacle. The annular contacts of the receptacle extend through an arc of substantially three hundred and sixty degrees, so that ordinarily it is never necessary to twist the plug cap in effecting its insertion into the receptacle, except perhaps when the contact blades are presented to the spacing members 5, 5 of the receptacle, in which case, it is only necessary to turn the plug cap a slight amount in either direction to effect its connection with the receptacle.

One of the most common causes of failure in plug caps as was previously suggested, is caused by the strain on the strands of the cord due to twisting of the plug cap. Ordinarily, in effecting attachment of a plug cap, the plug is always rotated in the same manner by most persons, namely in a clockwise direction, in order to bring the contact blades of the plug cap into registry with the contacts of the conventional receptacle, which, of course, require that the plug always be inserted in substantially the same position in the receptacle.

In the present invention, however, connection between the receptacle and plug cap may be eifected in an indefinite number of positions of the plug cap, and by reason of this arrangement, a better electrical contact is effected over a longer period of time in the use of the plug than is possible with a receptacle employing conventional contacts. The electrical connection too in the present connecter may be improved by slightly twisting the plug cap after it has been inserted into the receptacle.

The plug body 22 shown in Figures 5 and 6 comprises a screw shell 23 which is adapted for reception in an ordinary lamp socket. The threaded portion of the plug body forms one of the terminals thereof and a second terminal 24 is provided centrally of the lower end as is customary in plug bodies of this type. The contact 24 is connected to a hollow cylindrical contact member 25 located centrally of the plug body. The screw shell 23 is connected to an annular contact member 26 located in an annular groove 21, spaced from and surrounding the central contact member. The face of the plug body is formed with a shoulder 28 at its outer edge to facilitate and guide an attachment plug cap when connection is desired to be effected with I the plug body.

In Figures '7 and 8, there is illustrated an attachment plug cap 30 having contact blades 3| adapted for interlocking engagement with the contact members 25 and 28 of the plug body. The

' 38. The body of the plug is provided with a central bore in which a U-shaped contact member 48 is received. The adapter is provided with a pair of contact blades 4| by means of which connection may be made with the terminals of a screw shell body or those of a standard receptacle. The central portion of the body of the adapter is downwardly tapered at 42 towards the central opening of the body of the adapter for purpose of facilitating connection with a special type of plug cap which will be described in detail presently.

The plug cap provided for use in connection with the adapter shown in Figures 9 and 10 is illustrated in Figures 11 and 12 and it comprises a plug cap having a body portion 43 which supports a centrally disposed, circular rod-like terminal contact member 44 which is adapted for reception in the central opening of the adapter. The contact member 44 has an annular groove 45 adjacent its outer end so as to provide for detachable interlocking engagement with the U- shaped contact spring 40. A resilient contact member 45 is carried by the body of the plug cap adjacent the outer edge thereof. This member is U-shaped or V-shaped in cross-section and is configurated so that it may be readily inserted into the annular groove 31 of the adapter for contact with the annular contact member 38. The conductor strands 41 of the cord 48 are connected to the contact members 44 and 46 in the usual manner, as for example, by the screws 50, 58.

In Figures 13 and 14 there is illustrated a flushtype receptacle which is adapted for effecting contact between a standard or conventional plug cap, or with either of the plug caps shown in Fi'gr ures.4 and 8 of this application. This receptacle comprises a body portion 5| carried by a fitting 52 having offset portions 53 with suitable holes 54 by means of which the receptacle may be secured by mounting screws (not shown) to a plane surface.

The body of the receptacle is provided with an annular shoulder 55 extending around the edge of the plug for the purpose of guiding the contact blades of an attachment plug cap into registry with the contacts of the receptacle. In the present case, the contacts of the receptacle, are in the form of inner and outer concentric annular sleeves 56 and 51 respectively which are located in annular spaces 58 and 68 formed in the body of the receptacle. A concentrically positioned post or pin 63 is located in the annular space 58 and this post or pin has a rounded top to assist in guiding one of the contact blades of an attachment plug into the annular space about the pin. The contact members 55 and 51 are connected to conductors 5|, 8| in any suitable manner, as for example, by means of soldered joints and the conductors 5|, 5| are provided with terminals having screws 62, 52 by means of which they may be connected to suitable current supply conductors.

Many details of the various modifications illustrated herein are interchangeable, one with the other, as for example, the contact members of the connecters shown in Figures 1, 5, 9 and 13, and other combinations of the various elements disclosed herein will readily suggest themselves to those skilled in the art towhich this invention relates.

Furthermore, it is to be understood that the particular forms of plug caps shown and described, and the particular procedure set forth are presented for purposes of illustration and ex planation and that various modifications of said apparatus and procedure may be made without departure from the invention as defined in the appended claims.

Having thus described my invention what I claim is:

1. A detachable two-piece electrical connecter comprising, a receptacle part having a substantially fiat face with a connecter blade receiving opening or openings of annular configuration ex-,

tending throughout the major portion of a circle and concentric, internally disposed, radially spaced, annular contact members perpendicular to the face of the receptacle part, and a cooperating connecter part having substantially fiat, spaced, parallel, connecter blades adapted for contact with such annular members, the blades of said cooperating connecter part being adapted for use with a conventional receptacle, the edges of said blades and the faces of said contact members being configurated for effecting detachable, interlocking, contact engagement between the connecter parts.

2. A detachable electrical connecter comprising, a plug cap having a pair of substantially flat blades adapted for use in connection with a conventional receptacle, and a cooperating connecter part or reeeptaclefor receiving the plug cap, said connecter part having a pair of terminals adapted for contact with the blades of the plug cap, one of said terminals being of annular configuration and the other of said terminals being located in a centrally disposed recess in the face of the cooperating connecter part and surrounded by said annular terminal, the edges of said blades and the faces of said contacts being configurated for effecting detachable, interlocking, contact engagement between the connecter parts.

3. A detachable electrical connecter comprising, a plug cap having a pair of substantially flat blades adapted for use in connection with a conventional receptacle, and a cooperating connecter part or receptacle for receiving the plug cap, said connecter part having a pair of terminals adapted for contact with the blades of the plug cap, one at least of said terminals being of annularcurvature so as to permit insertion of the blades of the plug cap in different angular posicomprising, a receptacle part having a pair of concentrically arranged contacts the outer one of which is in the form of an annular member and the inner one of which is located in a recess disposed centrally in the face of the receptacle part, and a cooperating plug cap part having a pair of flat, substantially identical blades adapted for detachable engagement with the contacts of said receptacle, the blades of said plug cap being adapted for use with a conventional receptacle,

the edges of said blades and the faces of said contacts being configurated for effecting detachable, interlocking, contact engagement bebetween the blades and contacts of the connecter parts.

5. A detachable two-piece electrical connecter comprising a receptacle part having a pair of contacts one of Which is in the form of an annular member and the other of which is located in a recess disposed centrally in the face of the receptacle part and a cooperating plug cap part having a pair of substantially identical, flat blades adaptedfor contact with said contacts, the blades of said cooperating connecter part being adapted for use with a conventional receptacle, the edges of said blades and the faces of said contacts being configurated for effecting detachable, interlocking, contact engagement with each other.

LEROY H. LOOMIS. 

